"We are very excited to be launching Mac OS X Lion tomorrow," said Peter Oppenheimer, Apple's CFO, during the early stages of a quarterly earnings call with Wall Street analysts. Oppenheimer did not name a time of day Wednesday for Lion's release.

Previously, Apple had said only that it would ship Lion during July, but had refused to state a specific date.

In an email urging developers to submit their programs to the Mac App Store last week, Apple said the upgrade would be available "soon."

Apple provided a "gold master" build of Lion -- the tag some developers use for software that has been completed and is ready to ship -- on July 1, but did not seed them with another version.